交换单链表中相邻的两个点(人搜)

/*************************************************************
* file:reverse_twins_node_of_list.c
* brief:交换单链表中相邻的两个点
* yejing@2015.1.20    1.0      creat
*************************************************************/
#include <stdio.h>
#include <stdlib.h>

typedef struct _node_t{
struct _node_t *next;
int value;
}node_t;

node_t* creat_list(int n){
if(!n)
return NULL;
int i = 1;
node_t* phead = (node_t*)malloc(sizeof(node_t));
phead->next  = NULL;
phead->value = 1;
if(!phead)
return NULL;
node_t *p, *q;
p = q = phead;

for(i = 1; i < n; ++i){
q = (node_t*)malloc(sizeof(node_t));
p->next = q;
p = q;
p->value = i + 1;
}
return phead;
}

node_t* reverse_twins_node_of_list(node_t* phead){
if(!phead)
return NULL;
if(!phead->next)
return phead;
int i = 2;
node_t* n = phead;
phead = phead->next->next;
while(i){
node_t* m = n;
n = n->next;
m->next = phead;
phead = m;
--i;
}
phead->next->next = reverse_twins_node_of_list(phead->next->next);
return phead;
}

void show_list(node_t* phead, int before_after){
if(!phead)
return;

node_t* tmp = phead;
if(before_after)
printf("before transfer ");
else
printf("after  transfer ");
printf("list is:");
while(tmp){
printf(" %d", tmp->value);
tmp = tmp->next;
}
printf("\n");
return;
}

int main(int argc, char* argv[]){
int count;
printf("input list node count:\n");
scanf("%d", &count);
getchar();
node_t* phead = creat_list(count);
show_list(phead, 1);
phead = reverse_twins_node_of_list(phead);
show_list(phead, 0);

return 1;
}